How many species exist on Earth?

How many species exist on Earth? Well, no one really knows exactly, but there are some reasonable estimates. One figure, estimated by the Census of Marine Life Scientists, is posited to be at 8.7 million based on taxonomic methodology. Of this 8.7 million, at least 85% of the species on land and in sea still have yet to be identified and cataloged. It is amazing to think that we only know about 15% of the life found on Earth. There remains much to be discovered.

Recently, researchers at the Smithsonian used the method of DNA barcoding to identify 168 crab species in a relatively small 20.6 feet square feet area of coral reef. This is almost as many crab species that have been identified in all the seas of Europe. This then begs the question; can more than 8.7 million species on Earth be identified through DNA barcoding? It is possible. Some scientists estimate that as many as 100 million species may be found on Earth. If this estimate is closer to to actual amount of current species living on Earth, then DNA barcoding will be the most efficient method used to identify species that currently exist on Earth. DNA barcoding is a relatively quick and easy way to identify species and this can lead to future tracking of species within ecosystems. By looking at the DNA of closely related species it is also possible to find species that may similarly create substances that can be used as medicine or used to advance technology.

It is important that we try to identify and catalog as many species as possible. Coral reefs, like the one described above, are immensely diverse, and yet are some of the most threatened environments in the world due to the human impact of pollution and overharvesting. We may never truly know the amount of biodiversity that the Earth has and is capable of having if we are using our time destroying it.